IBM's first entry into direct memory access, RAMAC in 1957, had a 5 megabyte storage capacity existing on fifty 24 inch data storage discs. By the 1980s, the rate at which areal density increased yielded a single 5.25 inch disc with the same 5 megabyte storage capacity. The industry has continued to evolve into ever-smaller form factors according to a standardized scaling methodology. Today, the 5.25 inch form factor is obsolete, having been replaced with the 3.5 inch and 2.5 inch form factors, and more recently with one-inch and sub-one-inch form factors. This evolution has also reduced the form factor profile, resultingly decreasing the material thicknesses of components forming the enclosure.
The evolution driving the scaling methodology has been skewed by the proliferation of consumer products employing disc drives. This market is extremely cost sensitive, driving a trend away from base members made from aluminum castings in favor of base members made from stampings. In order to achieve the necessary stiffness from a stamped part, a steel material such as stainless steel or cold rolled steel is preferably used. However, the base member advantageously provides precise mounting surfaces for ensuring proper parallelism between the data storage disc and other components interacting with the disc. A base made from steel makes secondary machining operations of such critical mounting surfaces problematic in comparison to machining aluminum. With the shift to steel, cutter tooling replacement and machining cycle times, for example, have become significant opportunities for product cost reductions.
The future demand will be for ever-smaller disc drive enclosures. As more powerful electronics are packed into the same or smaller space, it will be necessary to stay abreast of the size requirements by miniaturizing and compacting mating assemblies, such as the mating of the base member with a printed circuit board, to the greatest extent possible. What is needed is a solution that provides a base member from a stamping with the necessary strength and parallelism attributes but with no or minimal secondary machining operations. It is to these improvements that the embodiments of the present invention are directed.